Foldable wheelchair and kit therefor

ABSTRACT

A foldable chair of a light-weight construction having a seat, a back, and front and rear leg structures and foldable between a use position and a storage position, includes a pair of casters mounted in spaced-apart relationship to the front leg structure for partially and rollably supporting the chair over a supporting surface, a pair of wheels mounted in spaced-apart relationship to the rear leg structure for partially and rollably supporting the chair over the supporting surface, and at least one elongated strut element extending between the front leg structure and the rear leg structure, the strut element being connected swingably at one of its end portions to the associated leg structure and being movably connected at its opposite end portion to its associated leg structure so that the strut element may be swung between a substantially horizontal use position and a storage position. The foldable chair further includes a pair of large ambulatory wheels journaled for rotation on an axle connected to the rear leg structure, a foldable footrest connected to the front leg structure, and a package carrier support extending horizontally between the front and rear leg structures.

United States Patent [1 1 Ingerson 1 June 3, 1975 1 FOLDABLE WHEELCHAIRAND KIT THEREFOR [22] Filed: Nov. 28, 1973 [2]] Appl. No.: 419,607

[52] U.S. C1 297/39; 16/29; 280/36 R; 280/79.1; 280/242 WC; 297/D1G. 4[51] Int. Cl. A47C 4/28 [58] Field of Search 297/39, DIG. 4', 280/34 R,280/36 R, 79.1, 242 WC; 301/1; 16/29, 31 R FOREIGN PATENTS ORAPPLICATIONS 447,430 5/1936 United Kingdom 297/39 910,778 11/1962 UnitedKingdom 280/79.l

Primary Examiner-Roy D. Frazier Assistant ExaminerWi1liam E. LyddaneAttorney, Agent, or FirmBernard L. Kleinke; Thomas W. Speckman; LeonardJ. Kalinowski 5 7 ABSTRACT A foldable chair of a light-weightconstruction having a seat, a back, and front and rear leg structuresand foldable between a use position and a storage position, includes apair of casters mounted in spaced-apart relationship to the front legstructure for partially and rollably supporting the chair over asupporting surface, a pair of wheels mounted in spaced-apartrelationship to the rear leg structure for partially and rollablysupporting the chair over the supporting surface, and at least oneelongated strut element extending between the front leg structure andthe rear leg structure, the strut element being connected swingably atone of its end portions to the associated leg structure and beingmovably connected at its opposite end portion to its associated legstructure so that the strut element may be swung between a substantiallyhorizontal use position and a storage position. The foldable chairfurther includes a pair of large ambulatory wheels journaled forrotation on an axle connected to the rear leg structure, a foldablefootrest connected to the front leg structure, and a package carriersupport extending horizontally between the front and rear legstructures.

9 Claims, 8 Drawing Figures FOLDABLE WHEELCHAIR AND KIT THEREFOR Thepresent invention relates to a light-weight foldable wheel chair and akit therefor, and it more particularly relates to a light-weight chairfoldable between a use position and a storage position and having arollable undercarriage assembly.

Foldable wheel chairs have been employed by people of limited walkingability so that they may fold them into a storage condition to assume aconvenient size and shape, whereby the user may, for example, transportthe chair in its folded storage position in a vehicle. While such awheel chair is satisfactory for some applications, it is relativelyexpensive to manufacture and is unduly heavy in weight so that liftingand manipulating the bulky wheel chair is difficult and for some peopleimpossible to do. Therefore, it would be highly desirable to have awheel chair which is relatively inexpensive and light in weight, wherebyit would be convenient to use in that it would be readily transportableand could be stored with ease in small close spaces. Such a light-weightportable wheel chair should be readily and conveniently held in the handof the user or rolled along a supporting surface. Also, it would behighly desirable to have a kit for converting an inexpensivelight-weight foldable chair of the type made from aluminum and fabricweb material, whereby the low cost chairs could be discarded, ifdesired, after long use and the kit transferred to a new similar chair.

Therefore, it is the principal object of the present invention toprovide a new and improved light-weight and convenient to use and storefoldable wheel chair and kit for making same.

Briefly, the above and further objects may be realized in accordancewith the present invention by providing casters adapted to be connectedto the front leg structure of a foldable chair for partially androllably supporting it over a supporting surface, a pair of wheelsadapted to be connected to the rear leg structure of the chair forpartially and rollably supporting it over the supporting surface, and atleast one elongated strut element extending between the front legstructure and the rear leg structure, the element being swingablyconnected at one of its end portions to its associated leg structure andmovably connected at its opposite end portion to its associated legstructure so that the strut element may be swung between a substantiallyhorizontal use position and a storage position. The strut elementprovides structural strength needed for enabling a lighbweight chair toserve as a wheel chair, since a wheel chair in use oftentimes issubjected to rearwardly or forwardly directed forces which mightotherwise tend to cause the chair to fold or collapse. The presentinvention also contemplates the provision of two large ambulatory wheelsjournaled for rotation on an axle mounted on the rear leg structure ofthe chair, and also the present invention contemplates the use of afootrest connected to the front leg structure of the chair and a packagecarrier support connected between the front and rear leg structures.

These and other objects will become more apparent by reference to thefollowing detailed description and accompanying drawings, wherein:

FIG. I is a pictorial view of the foldable wheel chair constructed inaccordance with the present invention;

FIG. 2 is an enlarged elevational view of the chair in its foldedposition with the ambulatory wheels and footrest removed;

FIG. 3 is a cross-sectional fragmentary enlarged view of one of thecasters and mounting brackets therefor for the chair of FIG. 1;

FIG. 4 is an enlarged cross-sectional fragmentary view of one of therear wheels and its mounting bracket of the chair of FIG. 1;

FIG. 5 is an enlarged fragmentary cross-sectional view of one of thestrut elements of the chair of FIG.

FIG. 6 is a crosssectional view of the strut element of FIG. 5 takensubstantially along the line 66 thereof;

FIG. 7 is a fragmentary enlarged elevational view of the back portion ofthe chair of FIG. 1, illustrating the ambulatory wheel axle assembly;and

FIG. 8 is an enlarged cross-sectional view of the assembly of FIG. 7taken substantially along the line 88 thereof.

Referring now to the drawings, and more particularly to FIGS. 1 and 2thereof, there is shown a foldable wheel chair 10, which is constructedin accordance with the present invention. As shown in FIG. 1, the chairIt) comprises generally a conventional lightweight foldable chair l2composed of light-weight metal and fabric material (generally referredto as a lawn chair), and a rollable undercarriage assembly kit generallyindicated at 14. The chair 12 generally comprises a seat 16 pivotallyconnected at its rear edge to the bottom edge of a back 18 which issupported from the ground by a front U-shaped leg structure 21 pivotallyconnected intermediate its ends to the seat 16 with its ends pivotallyconnected to a pair of spacedapart arm rests 23 and 25, respectively,and by a rear U-shaped leg structure 27 pivotally connected intermediateits ends to the seat 16 with its ends pivotally connected to therespective arm rests 23 and 25. The assembly kit 14 generally comprisesa pair of front casters 29 and 31 mounted to the front leg structure 21by respective corner brackets 33 and 35, a pair of rear wheels 37 and 39similarly mounted to the lower corner portion of the rear leg structure27 by means of the respective corner brackets 42 and 44, a pair offoldable strut elements 46 and 48 pivotally connected between the frontand rear brackets 33 and 42 and between the front and rear brackets 35and 44 to maintain the chair 12 in its open or use position when itshould strike an immovable object during use, and a pair oflargeambulatory wheels 51 and 53 journaled for rotation on an axle assembly55 to enable the user to move the chair along a supporting surface. Itshould be noted that in FIG. I of the drawings, the chair 12 is rollablysupported by the front casters 29 and 31 and the rear ambulatory wheels51 and 53, the rear smaller wheels 37 and 39 being supported above theground when the ambulatory rear wheels are employed. If it is notdesirable to employ the ambulatory wheels, such as where another personis available to push the chair 12, the wheels 51 and 53 are readilyremovable so that the wheels 37 and 39 may be employed in their place ashereinafter described in greater detail. A plurality of fabric bands,such as the band 57, composed of fabric material similar to the fabricmaterial of the seat 16 and the back 18 of the chair 12 surrounds tautlyand extends across the strut elements 46 and 48 to form a packagecarrier support or rack under the seat 16. It should be noted that thebands forming the carrier support extend crosswise and are notinterwoven with front-to-back bands as employed in the chair 12 toenable the strut elements 46 and 48 to be folded upwardly when the chair12 is folded. A foot-rest 59 is pivotally connected to brackets 33 and35 and cantilevered out therefrom, the outer edge portion beingsupported by a pair of chains 62 and 64 suitably connected to thefootrest by brazing or the like with the free ends thereof connected tothe respective hooks 66 and 68 for attaching to the pivot points betweenthe leg structure 21 and the seat 16. The footrest 59 generallycomprises a rectangular frame 59A which removably hooks onto a pair ofstruck-out tabs 33A and 35A on the corner brackets 33 and 35,respectively. The frame is covered with fabric bands, such as the band69, in a woven arrangement in a similar manner to the seat 16 and theback 18.

As shown in FIG. 2, the chair 12 may be folded into its storage positionby first removing the wheels 51 and 53, the axle assembly 55, and thefoot-rest 59, so that the chair may be then folded into the position asshown in FIG. 2. If desired, the foot-rest 59 may remain attached to thebrackets 33 and 35, and then the chair may be folded into the positionas shown in FIG. 2, the wheels 51 and 53 together with the axle assembly55 may be inserted between the foot-rest 59 and the seat 16 with thechains 66 and 68 hooking onto any convenient portion of the chair 12 ifdesired.

Considering now the front corner brackets 33 and 35 in greater detailwith reference to FIGS. 1 and 3 of the drawings, the bracket 33 issimilar to the bracket 35, and thus only the bracket 33 need bedescribed. The bracket 33 is generally tri-angular in cross-section andis cup-shaped to receive the complimentary-shaped corner portion of theleg structure. The shape and design of the corner bracket 33 enable itto fit many different kinds of existing foldable chairs. The bracket 33includes a front triangular wall 70 and a rear triangular wall 72 joinedsmoothly together in a contoured manner along their side and bottomedges, the walls 70 and 72 being composed of stiff light-weightmaterial, such as aluminum. In order to fasten the caster 29 to thebracket 33, a threaded post 74 extends from the upper swivel plate 75portion of the caster 29 through a hole in the bottom portion of thebracket 33 and tightened into a nut 76 fixed to the bracket 33 by asuitable tech nique, such as brazing. A plurality of screws 78 extendthrough aligned holes in the front wall 70 and the rear wall 72 and intonuts (not shown) fastened as by brazing to the outer rear surface of therear wall 72 to secure the bracket 33 to the leg structure 21.

Considering now the rear brackets 42 and 44 with reference to FIG. 4,the brackets 42 and 44 are similar to one another and therefore only thebracket 42 need be described. The bracket 42 is also similar in size andshape to the front brackets and includes a front wall 81 and a rear wall83.

A bolt 85 extends through the wheel 33 to enable it to rotate on theunthreaded portion thereof, the threaded end portion of the bolt 85being threaded into a nut 87 brazed to the outside of the bracket 42 andthrough a hole 89 in the bracket 42 as shown in FIG. 4. A plurality ofscrews, such as the screw 90, extends through aligned holes in the frontand rear walls 81 and 83 and into a nut (not shown) brazed onto the backside of the wall 83.

Referring now to FIGS. and 6 of the drawings, the strut elements willnow be considered in greater detail.

The strut element 46 is similar to the element 48, and thus only theelement 46 need now be described in detail. The element 46 includes ashort rod 92 pivotally connected at 94 to the back side of the wall 72of the bracket 33, the opposite threaded end portion 96 of the rod 92being threaded into a turnbuckle 98 for adjusting the axial length ofthe element 46. A rod 101 has one of its ends 103 threaded into theturnbuckle 98 and has its other end pivotally connected at 105 to a rod107. In order to retain and limit the downward movement of the rods 101and 107 below a horizontal position as shown in FIG. 5, an end portion109 of the rod 107 extending from the pivotal connection 105 toward theturnbuckle 98 is bent into the form of a hook which fits over the rod101 between the turnbuckle 103 and the pivotal connection 105. Thus, therods 101 and 107 may freely pivot relative to one another in an upwarddirection, but they are limited by the end hook portion 109 from movingbelow the horizontal position shown in FIG. 5. Such an arrangement ishighly desirable since the chair 12 may be folded or unfolded withoutthe need for any additional manipulations of the strut elements.

The rear end portion 111 of the rod 107 is threaded into a secondturnbuckle 113 to further aid in the longitudinal adjustment of thestrut element 46, the turnbuckle 113 threadably receiving at itsopposite end a threaded end portion 115 of a rod 117 which in turn ispivotally connected at its opposite rear end to the wall 81 of thebracket 42 at 119. In order to fold the element 46, the rods 101 and 107are gripped by the hand of the user under the pivotal connection 105therebe tween, and the pivotal connection is then moved upwardly for ashort distance moving the two brackets 33 and 41 toward one another,whereby both of the strut elements 46 and 48 may be partially foldedupwardly to thereafter permit the chair 12 to be completely moved intoits folded position as illustrated in FIG. 2 of the drawings. As clearlyshown in FIG. 2, the combined length of the rods 92 and 101 and thecombined length of rods 107 and 117 may be adjusted independently whenthe strut element is in its foldable position, thereby enabling thefolded strut element to be adjusted into position within the confines ofthe folded chair. The various parts of the strut elements are composedof rigid material, such as aluminum, to permit the strut elements towithstand compressive forces acting on the strut elements tending tomove the legs toward one another and thus fold up the chair 12.

Considering now the axle assembly 55 in greater detail with reference toFIGS. 7 and 8 of the drawings, a pair of brackets 122 and 124 havingrespective rearwardly-extending hook end portions 126 and 128 fit overthe axle assembly 55 and are fastened at their lower end portions by thescrews 130 and 132 and the screws 134 and 136, respectively, to the rearsides of the respective brackets 42 and 44, whereby the rear end portionof the chair 12 is carried rollably by the axle assembly 55 supportedabove the ground by the wheels 51 and 53. A pair of leaf springs 135 and137 are fastened to the back sides of the brackets 42 and 44,respectively, in overlying relationship with the respective brackets 122and 124, the springs 135 and 137 being secured to the back sides of thebrackets 122 and 124, respectively, by the same screws 130 and 134fastening the respective brackets 122 and 124 to the respective cornerbrackets 42 and 44. As best seen in FIG. 2, the leaf springs. such asthe spring 135, have an upwardly and outwardly-extending bent portion tohelp retain the axle assembly 55 seated against the hook portions of thebrackets 122 and 124, g

The axle assembly 55 includes an inner split tube 138 which fitstelescopically within a pair of equal diameter, axially aligned tubes141 and 143 to enable the axle assembly 55 to be longitudinally adjustedin length. [n this regard, the hook brackets 126 and 128, as shown inFIG. 7, are positioned between the respective pair of retaining annularexternal ridges 14S and 146 and the pair of retaining external annularridges 149 and 150 to limit the axial movement of the axle assembly 55.However, in accordance with the principles of the present invention, ifit is desired to employ the wheel chair of the present invention in anarea where space is limited such as in a residence, the smaller rearwheels 37 and 39 may be simply removed by removing the bolts retainingthem to their respective brackets, whereby the axle assembly 55 may beshortened by moving the tubes 141 and 143 toward one another until thehook portions 126 and 128 engage the respective tubes 141 and 143between the ridge 146 and an axially outwardly spaced-apart annularretaining ridge 147 and between the ridge 150 and an axially spacedapartouter retaining annular ridge 152. It should be understood that theretaining annular ridges may either be in the form of an integral memberor in the form of an attachment, such as an O-ring.

In order to removably attach the ambulatory wheels 151 and 153 to theaxle assembly 55, the wheel 53 will now be considered in greater detail,since the manner of attaching the ambulatory wheels to the axle assembly55 is similar to one another. A hub 154 of the wheel 53 is connectibleto the outer rim ofthe wheel via a plurality of spokes, such as thespokes 156 and 158, and the hub 154 rotatably fits over a bushing 159,which in turn surrounds the tube 143. An annular magnet 162 has acentral hole 163 for receiving the tube 143. The magnet 162 is apermanent magnet, and is attracted to the tube 143 magnetically to beremovably secured thereon, and similarly the magnet 162 is positionedagainst the hub 152 and the bushing 159 to be magnetically attachedthereto to releasably retain the wheel 53 on the bushing 159. It shouldbe understood that other types of bushings or bearings, such as rollerbearings, may also be employed.

While there is described above the principles of the present inventionin connection with specific apparatus, it is to be clearly understoodthat this description is made only by way of example and not as alimitation to the scope of the present invention.

1. In a foldable chair of the type having a lightweight frame withinterwoven flexible webs secured thereto to form a seat, a back, andfront and rear leg structures, the chair foldable between a use positionand a folded storage position, a rollable undercarriage assemblycomprising:

a pair of casters connected to the front leg structure for partially androllably supporting the chair over a supporting surface;

a pair of wheels connected to the rear leg structure for partially androllably supporting the chair over the supporting surface;

at least one elongated folable strut element extending between the frontleg structure and the rear leg structure;

first pivoting means for connecting swingably one of the end. portionsof said strut element to its associated leg structure;

second pivoting means for connecting movably the opposite end portion ofsaid strut element to its associated leg structure so that said strutelement may be swung between a substantially horizontal use position anda storage position; and

said strut element including a pair of first and second memberspivotally connected together, third and fourth members pivotallyconnected respectively to said first and second pivoting means, andfirst and second adjusting means respectively connecting said first andthird members together and connecting said second and fourth memberstogether for adjusting the overall length of said first and thirdmembers and said second and fourth members when they are arranged insubstantial axial alignment in the use position and for adjustingindependently the combined length of said first and third members andthe combined length of said second and fourth members when said strutelement is in its folded position, thereby enabling the folded strutelement to be adjusted into position within the confines of the foldedchair.

2. An assembly according to claim 1, wherein one of said first andsecond members includes a hook for limiting downward motion of saidfirst and second members substantially below a horizontal position whenthe chair is in its use position.

3. An assembly according to claim 2, further including large ambulatorywheels positioned near the seat, and an elongated axle assembly mountedon the undercarriage assembly for rotatably supporting said large wheelson opposite sides of the seat, said axle assembly being adjustable insize longitudinally to position adjustably said ambulatory wheels atdifferent spacedapart positions.

4. An assembly according to claim 3, wherein said axle assembly includesa split tube, and a pair of axially aligned outer tubes fortelescopically receiving said split tube, said ambulatory wheels andsaid tubes being composed of metal, said ambulatory wheels beingjournaled for rotation on said outer tubes, a pair of magnets positionedon the outer ends of said outer tubes for attracting said wheels to saidouter tubes.

5. An assembly according to claim 2, wherein each one of the front andrear leg structures is U-shaped, a rear pair of generally flattened,hollow cup-shaped corner brackets connected to the first-mentionedwheels for fitting over and receiving the rear corners of the rear legstructures, a front pair of generally flattened, hollow cup-shapedcorner brackets connected to said casters for fitting over and receivingthe front corners of the front leg structure.

6. A kit adapted to be attached to a foldable chair of the type having alightweight frame with interwoven flexible webs secured thereto to forma seat, a back, and a U-shaped front leg structure and a U-shaped rearleg structure and foldable between a use position and a storageposition, comprises:

a rear pair of generally flattened. hollow cup-shaped corner bracketsadapted to fit over and to receive the comers of the rear Ushaped legstructures and adapted to be secured in place thereon;

a pair of wheels connected to the rear pair of brackets for partiallyand rollably supporting the chair over the supporting surface;

a front pair of generally flattened. hollow cup-shaped corner bracketsadapted to fit over and to receive the corners of the front U-shaped legstructure and adapted to be secured in place thereon; a pair of castersconnected to the front pair of brackets for partially and rollablysupporting the chair over a supporting surface; and at least oneelongated strut element connected between one of said rear pair ofbrackets and one of said front pair of brackets.

7. A kit according to claim 6, wherein said strut element comprisespivotally interconnected first and second members, each one of saidfirst and second members including a pair of rods, and means foradjustably connecting together said rods end-to-end so that the overalllength of said rods can be adjusted.

8. A kit according to claim 6, further including large ambulatory wheelspositioned near the seat, and an elongated axle assembly, adapted to bemounted on said rear pair of brackets for rotatably supporting saidlarge wheels on opposite sides of the seat. said axle assembly beingadjustable in size longitudinally to position adjustably said ambulatorywheels at different spaced-apart positions.

9. A kit according to claim 8, wherein said axle assembly includes asplit tube, and a pair of axially aligned outer tubes for telescopicallyreceiving said split tube, said ambulatory wheels and said tubes beingcomposed of metal, said ambulatory wheels being journaled for rotationon said outer tubes, a pair of magnets positioned on the outer ends ofsaid tubes for attracting said wheels to said outer tubes.

i i 1 Q

2. An assembly according to claim 1, wherein one of said first andsecond members includes a hook for limiting downward motion of saidfirst and second members substantially below a horizontal position whenthe chair is in its use position.
 3. An assembly according to claim 2,further including large ambulatory wheels positioned near the seat, andan elongated axle assembly mounted on the undercarriage assembly forrotatably supporting said large wheels on opposite sides of the seat,said axle assembly being adjustable in size longitudinally to positionadjustably said ambulatory wheels at different spaced-apart positions.4. An assembly according to claim 3, wherein said axle assembly includesa split tube, and a pair of axially aligned outer tubes fortelescopically receiving said split tube, said ambulatory wheels andsaid tubes being composed of metal, said ambulatory wheels beingjournaled for rotation on said outer tubes, a pair of magnets positionedon the outer ends of said outer tubes for attracting said wheels to saidouter tubes.
 5. An assembly according to claim 2, wherein each one ofthe front and rear leg structures is U-shaped, a rear pair of generallyflattened, hollow cup-shaped corner brackets connected to thefirst-mentioned wheels for fitting over and receiving the rear cornersof the rear leg structures, a front pair of generally flattened, hollowcup-shaped corner brackets connected to said casters for fitting overand receiving the front corners of the front leg structure.
 6. A kitadapted to be attached to a foldable chair of the type having alightweight frame with interwoven flexible webs secured thereto to forma seat, a back, and a U-shaped front leg structure and a U-shaped rearleg structure and foldable between a use position and a storageposition, comprises: a rear pair of generally flattened, hollowcup-shaped corner brackets adapted to fit over and to receive thecorners of the rear U-shaped leg structures and adapted to be secured inplace thereon; a pair of wheels connected to the rear pair of bracketsfor partially and rollably supporting the chair over the supportingsurface; a front pair of generally flattened, hollow cup-shaped cornerbrackets adapted to fit over and to receive the corners of the frontU-shaped leg structure and adapted to be secured in place thereon; apair of casters connected to the front pair of brackets for partiallyand rollably supporting the chair over a supporting surface; and atleast one elongated strut element connected between one of said rearpair of brackets and one of said front pair of brackets.
 6. A kitadapted to be attached to a foldable chair of the type having alightweight frame with interwoven flexible webs secured thereto to forma seat, a back, and a U-shaped front leg structure and a U-shaped rearleg structure and foldable between a use position and a storageposition, comprises: a rear pair of generally flattened, hollowcup-shaped corner brackets adapted to fit over and to receive thecorners of the rear U-shaped leg structures and adapted to be secured inplace thereon; a pair of wheels connected to the rear pair of bracketsfor partially and rollably supporting the chair over the supportingsurface; a front pair of generally flattened, hollow cup-shaped cornerbrackets adapted to fit over and to receive the corners of the frontU-shaped leg structure and adapted to be secured in place thereon; apair of casters connected to the front pair of brackets for partiallyand rollably supporting the chair over a supporting surface; and atleast one elongated strut element connected between one of said rearpair of brackets and one of said front pair of brackets.
 7. A kitaccording to claim 6, wherein said strut element comprises pivotallyinterconnected first and second members, each one of said first andsecond members including a pair of rods, and means for adjustablyconnecting together said rods end-to-end so that the overall length ofsaid rods can be adjusted.
 8. A kit according to claim 6, furtherincluding large ambulatory wheels positioned near the seat, and anelongated axle assembly, adapted to be mounted on said rear pair ofbrackets for rotatably supporting said large wheels on opposite sides ofthe seat, said axle assembly being adjustable in size longitudinally toposition adjustably said ambulatory wheels at different spaced-apartpositions.